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ADVANCED COMBUSTION SYSTEMS
CRC Project No. AVFL-13
Leaders: S. W. Jorgensen
K. J. Wright
Scope and Objective
The objective of this project is to identify
fuel chemistry that impacts operation in 'gasoline' homogenous charge
compression ignition (HCCI) engines.
Current Status and Future Program
This project started in 2004. Both rebreathing-
and recompression-based engine designs were explored.
Ten gasoline-like test fuels of varying octane
quality, composition, and distillation were tested on a single cylinder, 575cc
displacement engine equipped with a hydraulic variable valve train (VVT) and a
gasoline direct injection (GDI) system.
These fuels were tested
using three different HCCI operating modes:
- Re-compression early
injection (RCEI),
- Re-compression split
injection (RCSI), and
- Re-breathing early
injection (RBEI).
For each mode, three engine
operating conditions were investigated:
- 1.5 bar IMEP at 1000
rpm,
- 3 bar IMEP at 2000
rpm, and
- 5.5 bar/deg of maximum
rate of pressure rise at 3000 rpm
These three operating
conditions represent, respectively: near-idle conditions, mid-HCCI load
conditions, and high-speed HCCI conditions.
The ten gasoline-like test fuels were blended
from four common refinery streams for blending commercial gasoline: (A)
reformate [about 55% aromatic], (B) alkylate [about 88% iso-paraffin], (C) cat
cracker gasoline [about 45% olefin], and (D) straight run gasoline [about 24%
normal paraffin] (n-paraffin). These four streams reflect the most commonly used
blend stocks in finished gasoline. Normal butane was added to bring each test
fuel up to a consistent, nominal 7 psi vapor pressure.
The committee
selected AVL to conduct this study through a competitive solicitation process.
AVL began the project in January 2005. Additional control systems were added to
the test engine and the test fuel matrix was developed in cooperation with
committee membership. The Final Report was issued in February 2007 and is posted
on the CRC website.
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